A couple weeks ago, astronomers spotted black holes that were ten billion times more massive than our Sun, setting new records for the biggest black holes ever found. NASA has spotted another record-setting black hole...although it's not quite as impressive.
The black hole is part of a binary system with the catchy name IGR J17091-3624. It shares the system with a normal star, from which the black hole leeches gas to create a massive disk of material around it - you can see it in the artist's conception up top. The gas is heated to millions of degrees and begins to emit X-rays. By comparing the cyclic X-ray patterns - known as heartbeats- emitted from this disk with that around another black hole, we can estimate the mass of IGR J17091-3624.
The other black hole, GRS 1915+105, is estimated to be about 14 times the Sun's mass, which is nearing the upper limit for a black hole formed from the collapse of a single star. Using NASA's Rossi X-ray Timing Explorer (RXTE), astronomers were able to determine that IGR J17091-3624 was much, much smaller. In fact, it's probably only three times as massive as the Sun, which is dangerously close to the minimum amount of mass needed to create a black hole in the first place.
If its original star had been any smaller, it would have lacked sufficient gravity to collapse in on itself. As such, this black hole may actually have a firmer grasp on its record than those 10-billion-solar-mass behemoths. After all, a black hole can always get bigger, but we're running out of room for black holes to get any smaller.
Check out NASA for more. Artist's conception by NASA/Goddard Space Flight Center/CI Lab.